How to Track Improvements Over Time

Purpose

Provide a practical approach for tracking performance improvements over time after Speed Layer installation.

Focus on trends, not single tests

Performance varies by device, network, and page content. Track improvements using time windows and percentiles rather than one off runs.

Recommended approach

1) Choose key pages

Track at least:

• Homepage
• SRP
• VDP
• Lead form pages

2) Track Core Web Vitals

Core Web Vitals are widely used and map well to shopper experience.

Google reference:

• Core Web Vitals https://web.dev/vitals/

3) Use percentile based reporting

When possible, focus on p75 (75th percentile) because that aligns with how Google evaluates CWV performance for ranking.

Public reference:

• Chrome User Experience Report (CrUX) https://developer.chrome.com/docs/crux/

4) Break down by device

Mobile and desktop performance often differ significantly. Track them separately.

5) Compare before and after

Use a consistent time window and compare against a baseline period. Avoid changing multiple things at once when you want clean attribution.

What to watch for

• Improvements that hold over time, not just the first few days
• Differences by page type (homepage vs SRP vs VDP)
• Regressions caused by new third party tags or platform changes

Related pages

• Why Real User Experience Matters More Than Scores
• What Metrics Dealers Should Care About
• Reading Trends vs One-Time Scores